1. Field of the Invention
The present invention relates to a hermetic compressor, more particularly, a valve apparatus for a hermetic compressor, which drives facilely a refrigerant discharge valve so as to improve a refrigerant discharge efficiency.
2. Description of the Related Art
Generally, there are various kinds of hermetic compressors such as a reciprocating compressor, a linear compressor and a rotary compressor. Most compressors are provided with a valve apparatus which controls an entrance of a refrigerant into a compressing chamber.
As shown in FIG. 6, a valve apparatus of the conventional reciprocating compressor comprises a cylinder head 11 which is coupled to a side of a cylinder block (not shown) of the compressor, and a valve plate 12 which is interposed between the cylinder head 11 and the cylinder block. A discharge valve 13 and a discharge backer 14 are riveted to the valve plate 12.
Here, the discharge backer 14 is curved from a fixed end riveted to the valve plate 12 toward a free end thereof, i.e., the cylinder head 11. This prevents the discharge valve 13 from having an unnecessary operating width, when the discharge valve 13 is operated, so that the discharge valve 13 properly performs an open-and-shut action.
However, in the conventional discharge backer 14, since a surface, which is contacted wish the discharge valve 13, is formed into a plane, an oil film is formed on the surface of the discharge backer 14 by oil which is discharged together with refrigerant gas during the open-and-shut action of the discharge valve 13. Frequently, the discharge valve 13 to be contacted with the discharge backer 14 is closely contacted with the surface of the discharge backer 14 due to an oil viscosity. Therefore, there is a problem that the discharge valve 13 can not secure its own equal driving property. As disclosed above, if the discharge valve 13 can not show the equal driving property, a part of the discharged refrigerant flows backward into a compressing chamber during a suction stroke by the delay of a returning action of the discharge valve 13. Therefore, there is other problem that a compressing efficiency of the refrigerant is lowered.
It is therefore an object of the present invention to improve the discharge backer which restricts and supports the operating width of the discharge valve so as to secure the equal and stable driving property of the discharge valve, thereby improving the compressing efficiency of the refrigerant.
To achieve the above objects and other advantages, there is provided an valve apparatus of a hermetic compressor, comprising a cylinder block in which a compressing chamber is formed; a valve plate which is disposed between the cylinder block and the a cylinder head coupled to a side of the cylinder block, and which is formed with a suction port and a discharge port; a discharge valve of which one end is fixed to the valve plate and the other end opens/closes the discharge port; and a discharge backer which is outwardly curved from its clamping end toward its free end so as to restrict an operating width of the discharge valve, characterized in that the discharge backer is provided with a protrusion which is projected toward the discharge backer so as to prevent the discharge valve from being closely contacted with the discharge backer.